Means for pumping liquids from gas producing wells



Jan. 29, 1963 N. w. GALLAWAY 3,075,467

MEANS FOR PUMPING LIQUIDS FROM GAS PRODUCING WELLS Filed March 25, 19605 JJLW I 56 3/ 39 I as NORRIS W. GALLAWAY INVENTOR.

Efilddd? Patented data. 29, 1963 free 3,975,467 MEANS Ffilk WJMPINGLlQUlDd FRGM GAS PRODUCENG WELLS Norris W. Gallaway, Fort Worth, Ten,assiguor to American Manufacturing Company of Texas, Fort Worth,

Tom, a corporation of Texas Filed Mar. 25, 195i Ser. No. 17,624 6Claims. (Cl. 103--44) This invention relates to well pumps and hasreference to a gas operated pumping unit particularly adapted to relievegas wells of water produced incidently from gas bearing formations.

In a number of gas fields there are wells which have a high gas volumepotential but which do not have sufficient shut-in pressure to exhaustintervening water. An accumulation of water within the bore of thesewells restriets and impedes gas production because the head of waterworks against and partially counteracts the available flow pressure ofthe gas. Generally, the rate of Water intrusion is very low in wells ofthis type, and, despite their inability to lift a head of water to thesurface, well head pressures exceed pipe line delivery requirements.Legally prescribed well spacings in Texas and other gas producing Statesoften render the construction and maintenance of electric service linesuneconomical for such intermittent use of low wattage motors as isrequired to evacuate intrusion water from gas wells. Servicingrequirements for gas or gasoline burning internal combustion engineslikewise lead to an evacuation cost which is greatly disproportionate tothe work actually expended in pumping relatively small quantities ofwater. Ideally, a pumping means which could operate without fuel costand with a minimum of attention, would 'be best suited to the describedproblem. In connection with this objective it should be noted thatexcess pressures wasted in delivery represent a normally dissipatedsource of energy which, if utilized, could provide power to evacuateintrusion water.

Accordingly, an object of the present invention is to provide a pumpingunit of limited volume capacity which can derive its power from the flowpressure of a gas well.

Another object of the invention is to provide a gas pressure operatedpumping unit which can operate effectively between relatively smallpressure differences at its input and exhaust systems.

A further object of the invention is to provide a pumping unit capableof deriving power from such pressure differences as exist between a wellhead and a pipe line delivery system.

A particular object of the invention is to provide a gas pressureoperated pumping unit which may be exhausted into the delivery system ofthe pipe line.

A related object of the invention is to provide means utilizing thepower normally wasted in pressure reduction for pipe line injection andfor operating a pumping unit thereby.

A further object of the invention is to provide gas operated means forexhausting intrusion water in a gas well.

An additional object of the invention is to provide a pumping unit forintrusion water and which unit may be operated without manual actuationor other special at tention.

These and other objects will become apparent from the followingdescription and the accompanying drawing, wherein:

FIGURE 1 is a side elevational and partially sectional view of a gaswell and a pumping unit as defined herein.

FIGURE 2 is a fragmentary side elevational view of the invention shownin operative connection with a gas separation tank.

FIGURE 3 is a fragmentary side elevational view of the inventionillustrating drive and speed reduction components thereof.

FEGURE 4 is a partially sectional front elevational view of the powerand driving systems of the invention.

In the drawing, a tubing string 10 is suspended within the casing 11 ofa gas well 12 and a tubing pump 13 including a piston 14 and a checkvalve 15 is positioned within the tubing 10 near the lower end thereof.A string of sucker rods 16 within the tubing string 10 is connected tothe piston 14 and extends therefrom to connection with a polish rod 17,the upper end of which projects through a stuffing box 18 on the upperend of the tubing 16. A skid 19 is supported by the surface of theground adjacent the casing head 2%. At opposite sides of the skid l9runners 21 constructed as spaced I-beam members are disposed in aparallel relationship with respect to one another and each is secured tothe lower surface of a horizontally positioned rectangular platform 22.Transverse beams 23 are likewise attached to the lower surface of theplatform 22 and extend between the runners 21. The longitudinal centerline of the skid 19 is positioned in radial alignment with the casinghead 20. Posts 24 project vertically and equidistantly from oppositesides of the skid l? and a horizontal pivot 25 is journaled at itsopposite ends to the respective upper ends of the posts 24. A walkingbeam 26 is positioned upon and perpendicularly attached to the pivot 25,and opposite ends of the walking beam project perpendicularly andoutwardly of the pivot in a vertical plane common with the longitudinalcenter line of the skid 19. One end of the walking beam 26 is providedwith a mulehead 27 in vertical alignment with the axis of the tubingIii; a bridle 23 depending from the mulehead 27 is attached to the upperend of the polish rod 17. The opposite or rearward end of the walkingbeam 26 carries a counterbalance 29 adapted to offset the polish rodload of the walking beam.

An air motor Bil is attached to and supported by the upper surface ofthe platform 22 at a position thereon forward of the posts 24. The airmotor 3i? is comprised of a block 31 including a horizontally disposedcylindrical chamber 32 and a cylindrical rotor 33 so positioned withinthe chamber that its axis is parallel with but eccentric to the axis ofthe chamber. A plurality of horizontally and radially disposed slots 34regularly spaced from one another about the circumference of the rotor33 each receive a vane 35, the outer edge of which is urged against thesurface of the chamber 32 by a spring positioned interiorily of the vane35 within each slot 34. A shaft 37 coaxially secured to the rotor 33 isjournaled at its opposite ends to face plates 38 and 39 respectivelybolted to the block 31 at opposite ends of the chamber 32. One endportion 40 of the shaft 37 projects outwardly of its face plate 32 and aspeed responsive driving mechanism, herein referred to as a centrifugalclutch 41, mounted on that end of the shaft, is adapted to receive anA-section drive belt 42 and engage the same when the shaft 37 reaches orexceeds a predetermined angular velocity. Although the floating conetype of centrifugal clutch 41 has been found to be satisfactory in thedescribed construction, it is to be understood that any of a variety ofcommercially available pulleys or centrifugal clutches may be so usedwithout departing from the spirit or scope of the present invention. Theillustrated clutch includes a stationary cone 43 coaxially afiixed tothe end portion 40 of the shaft 37 and a floating cone 44 positioned onthe shaft outwardly of the stationary cone in slidably opposedrelationship thereto. A housing 45 carried by the shaft 37 outwardly ofthe floating cone 44 encloses a mechanism (not shown) responsive torotation of the shaft and adapted to force the floating cone toward thestationary cone 43 when the shaft has attained a predetermined angularvelocity. A gear box 3. type speed reducer 46 is supported by andattached to the upper surface of the platform 22 at a position thereonrearward of the post 24. High speed and low speed shafts 47 and 48 arerespectively journaled to opposite sides of the case 49 of the speedreducer 46 and each of the shafts is disposed parallel to the shaft 37of the air motor 39; as shown in FIGURE 3, the low speed shaft 48 ispositioned rearwardly of the high speed shaft 47. The case is providedwith an access lid 50 to facilitate inspection and lubrication ofinternal components (not shown) of the speed reducer 46. A sheave 51adapted for engagement with the A-section belt 42 is mounted on one endof the high speed shaft 47 exteriorly of the case 49. A split block typecrank 52 is attached to one end of the low speed shaft 48 exteriorly ofthe case 49, and a pitman 53 is pivotally connected at one of its endsto the outer end of the crank and at its other end to a cross head 54carried by the walking beam 26 at a position thereon between the pivot25 and the counterbalance 29.

A gas flow line 55 extending through the casing head 26 communicates theannulus betweenthe tubing 16 and the casing 11 with the intake tube 56of the air motor 30. An injection line 57 communicates the exhaust tube58 of the air motor 30 with a pipe line delivery system (not shown). Abypass line 59 communicates the injection line 57 with one exhaust portof a three-way valve 60, the other exhaust port and inlet port of whichare connected in series to the gas fiow line with the inlet port of thethree-way valve connected to that portion of the flow line leading tothe casing head 20. The three-way valve 60 is adapted to alternatelycommunicate the annulus of the well with the intake tube of the airmotor or with the bypass line 59. A drain tube 61 communicating with theinterior of the tubing conducts exhausted Water to any suitable waterdisposal system.

In a well where appreciable quantities ofgas are exhausted with thewater, a separator tank 62 may be utilized with the invention asillustrated in FIGURE 2. In this arrangement, that end of the injectionline 57 which would otherwise be connected to a pipe line deliverysystem, is made to communicate with the drain tube 61 and the drain tubecommunicates with the interior of the separator tank 62. As is wellknown in the art, gas will collect in the upper end of the separatortank and may be bled off through a second injection line 63communicating the upper end of the tank 62 with a pipe line deliverysystem; water is drained from the lower end of the separator tank by asecond drain tube 64, and flow of water through the second drain tube isregulated by a float valve (not shown) within the tank which maintains alevel of water therein at a height above the second drain tube.

In operation, part or all of the gas metered into a pipe line may berouted through the air motor 3t) by selective adjustment of thethree-way valve 69. If gas is to flow continuously from the well into apipe line, the three-way valve 60 will normally be set so that theintake tube 5'6 of the air motor 30 is in communication with the annulusof the well. Gas from the well flows through the air motor 30 and causesthe rotor 33 and shaft 37 torotate at a speed such that the A-sectionbelt 42 is constantly engaged by the centrifugal clutch 41. The speedreducer 46 is constructed with a high input to output shaft speed ratioso that a very high angular velocity of the air motor shaft 37 producesa low angular velocity of the crank 52 and pitman 53. A properlyselected diameter for the sheave 51 can maintain a pumping rate whichslightly exceeds the water intrusion rate of a given well. Since thewater exhaustion rate must slightly exceed the intrusion rate in orderto assure the prevention of a water accumulation at the base of thewell, a considerably volume of gas Will be exhausted through the tubing10 in a continuous flow operation. As has 4 been described andillustrated in FIGURE 2, tubing gas may be captured in a suitableconnected separator tank 62.

The usual mode of gas production involves intermittent fiow. For thistype of operation a lower input to output shaft speed ratio is requiredof the speed reducer 46 and selection of a sheave 51 diameter will begoverned accordingly. When gas is to be metered into the pipe line thethree-way valve 60 is first set so that the annulus is communicated withthe intake tube 56 of the air motor 30. Under well pressure the airmotor 30 is accelerated and provided with sufficient momentum toovercome the inertia of the pumping unit before the centrifugal clutch41 engages the A-section belt 42 and starts the pumping operation. Ifthe accumulated head of water at the base of the well has risensufficiently during the period of inoperation to suppress gas flowpressure to a level where the difference in well pressure and meteringpressure is not sufficient to operate the pump, a small volume of gasmay be released to the atmosphere from the valve (not shown) customarilyprovided at the meter. As water is pumped from the well the availablegas pressure will rise and injection into the pipe line can becommenced. When the head of water at the base of the well has beenexhausted or sufficiently lowered the three-way valve 60 is then set sothat gas flows from the valve into the bypass line 59 and thence to theinjection line 57 and pumping is discontinued. It will be noted that thetubing 10 remains substantially filled with water at all times and theweight of the water and sucker rods 16 within the tubing is offset bythe counterbalance 29' so that the power required of the air motor 30 isonly that required to overcome the friction of various components,inertia of the system and energy expanded in displacing intrusion water.

The invention is not limited to the exemplary construction herein shownand described, but may be made in various ways within the scope of theappended claims.

What is claimed is:

1. A gas driven pumping unit for removing liquids from a gas well havinga casing and tubing, said pumping unit including a walking beam and apitman connected therewith: an air motor including a drive shaft, meanscommunicating the input of said air motor with the casing of a gas well,means communicating the exhaust of said air motor with the deliverysystem of a pipe line, a centrifugal clutch on said drive shaft, a drivemember engaging said centrifugal clutch, a speed reducer including ahigh speed shaft and a low speed shaft, means operatively connectingsaid drive member to said high speed shaft, a crank on said low speedshaft, means pivotally connecting said crank to the pitman of saidpumping unit, a sucker rod depending from the Walking beam of saidpumping unit and extending into the tubing of said well, and a pumpconnected to said sucker rod in said tubing.

2. A fluid evacuation system for a gas well comprising: a tubing stringin said well, a pump including a piston and a check valve in said tubingstring, a sucker rod connected to said piston in said tubing string, awalking beam pivotally supported above the surface of the ground, amulehead on said walking beam, 2. bridle connected to said mulehead andsupporting said sucker rod, an air motor including a drive shaft andhaving an intake and an exhaust tube, a centrifugal clutch mounted onsaid drive shaft, a speed reducer including a high speed shaft and a lowspeed shaft, a sheave mounted on said high speed shaft, a drive beltconnecting said sheave with said clutch, a crank on said low speedshaft, a pitman pivotally attached to and extending between said crankand one end of said walking beam, means communicating said intake tubeof said air motor with the casing of said well, means communicating theexhaust tube of said air motor with the delivery system of a pipe line,and bypass means alternately connecting said means communicating saidintake tube of said air motor with said exhaust tube of said air motor.

3. The invention as defined in claim 2 and wherein said bypass meansalternately connecting said means communicating said intake tube of saidair motor with said exhaust tube of said air motor includes a three-wayvalve in said intake tube of said air motor and wherein one exhaust portof said three-way valve communicates directly with the exhaust tube ofsaid air motor.

4. In a gas well including a tubing pump and a pumping unit of thewalking beam type, an air motor including a drive shaft and having anintake tube communieating With the casing of said well and havingexhaust means communicating with a pipe line, a speed reducer includinga high speed shaft and a low speed shaft, a speed responsive clutch onsaid drive shaft, power transmission means coupling said clutch to saidhigh speed shaft, a crank on said low speed shaft, and a pitmanpivotally connected to said crank and engaging the walking beam of saidpumping unit.

5. The invention as defined in claim 4 and wherein said exhaust meanscommunicating with a pipe line includes: a drain tube communicating withthe interior of the tubing of said tubing pump, a separator tankcommunicating with said drain tube, and an injector line communicatingthe upper end of said separator tank with said pipe line.

6. A gas driven pumping unit for removing liquids from a gas well havinga casing, said pumping unit including a walking beam and a pitmanconnected therewith, a rotary air motor including a drive shaft, meanscommunicating the input of said motor with the casing of said gas well,means communicating the exhaust of said rotary air motor with thedelivery system of a pipe line, a speed reducer including a high speedshaft and a low speed shaft, means operatively connecting said driveshaft to said high speed shaft, a crank on said low speed shaft, meanspivotally connecting said crank to said pitman of said pumping unit, asucker rod depending from the walking beam of said pumping unit andextending into said well and a pump connected to the end of said suckerrod in said well.

References Cited in the file of this patent UNITED STATES PATENTS245,101 Thayer et a1. Aug. 2, 1881 460,522 Bretherton Sept. 29, 1891531,537 Klein Dec. 25, 1894 1,132,329 Gamble et a1. Mar. 16, 19151,437,721 Clark Dec. 5, 1922 1,741,571 Ives Dec. 31, 1929 1,861,013Howard May 31, 1932. 2,071,393 Doherty Feb. 23, 1937 2,077,665 BennettApr. 20, 1937 2,142,552 Athy Jan. 3, 1939 2,408,075 Kowalski Sept. 24,1946 2,564,528 Ge-arin Aug. 14, 1951

1. A GAS DRIVEN PUMPING UNIT FOR REMOVING LIQUIDS FROM A GAS WELL HAVINGA CASING AND TUBING, SAID PUMPING UNIT INCLUDING A WALKING BEAM AND APITMAN CONNECTED THEREWITH: AN AIR MOTOR INCLUDING A DRIVE SHAFT, MEANSCOMMUNICATING THE INPUT OF SAID AIR MOTOR WITH THE CASING OF A GAS WELL,MEANS COMMUNICATING THE EXHAUST OF SAID AIR MOTOR WITH THE DELIVERYSYSTEM OF A PIPE LINE, A CENTRIFUGAL CLUTCH ON SAID DRIVE SHAFT, A DRIVEMEMBER ENGAGING SAID CENTRIFUGAL CLUTCH, A SPEED REDUCER INCLUDING AHIGH SPEED SHAFT AND A LOW SPEED SHAFT, MEANS OPERATIVELY CONNECTINGSAID DRIVE MEMBER TO SAID HIGH SPEED